discloses that a pressure level of fuel gas upstream of an injector is lower at start-up than that during ordinary operation of a fuel cell.
In the fuel cell system disclosed in JP2007-323873A, however, when inner gas of an anode passage in a fuel cell is replaced with air and the anode passage and a cathode passage each have the air during start-up, a lower pressure upstream of an injector causes a decreased injection volume of the injector and results in a delay to replace the air in the anode passage by hydrogen. Unfortunately, this causes the fuel cell to be polarized at a high potential for a long time.